Interesting read. The Stratolaunch carrier aircraft as a 21st century Glomar Explorer angle is one I have read about before. Frankly, I put a lot more
stock in it before they settled on the Pegasus XL as their launch vehicle. If the powers that be wanted to air launch some super-secret payload using
a Pegasus, they could just use a B-52, as was done for the first few Pegasus launches back in the early 90s.

Also, while the concept art with the Stratolaunch carrier lofting 3 separate Pegasus boosters looks really cool, there's no operational reason to ever
do that. If the payloads are going to VERY different orbital planes, the aircraft doesn't have enough range to reposition after the first and second
launches and then return to base. If the payloads are going to the same or nearly the same orbital plane, it would be cheaper to use a Falcon 9 (or,
depending on the payload, even an Atlas V) than 3 Pegasus rockets.

They're there. They're all the way down by the very tip of the nose. One side is cockpit, the other is launch control. Usually when it's in a hot
area like that, they put up a sun shade inside the cockpit to keep it from overheating. That can make it look like there are no windows, especially
in a shot from a distance like these are.

So each of those engines is almost 8' across, and there are six of 'em with what looks to be at least 7 to 8 feet between them, plus whatever out to
the tip from the outboard, and what ever the distance to the fuselage--monstrous just about covers it...

originally posted by: Forensick
If this aircraft replaces the first stage of a rocket, wouldn't the second stage have to burn for longer to get the projectile up to the speeds a
first stage would have generated by the same height?

I cant see point if falcon 9 is a reusable first stage, isn't it better than this?

Still nice to see a new aircraft, I hope it does find a solution to the problem its trying to solve.

What matters for getting into orbit is speed. Thus air launch can not replace the first stage. The advantage is mostly about being more flexible
regarding target orbit and weather.

It requires less fuel to get into orbit. You aren't having to make that initial massive burn to break free from the ground and get through the denser
air at low altitude, so you don't have to have as much fuel, or as many engines as you do with a larger rocket.

The principal advantage of a rocket being launched by a high flying airplane is that it need not fly through the low, dense atmosphere, the drag
of which requires a considerable amount of extra work and thus mass of propellant. Higher densities at lower altitudes result in larger drag forces
acting on the vehicle. In addition, thrust is lost due to over-expansion of the exhaust at high ambient pressure and under-expansion at low ambient
pressure; a fixed nozzle geometry cannot provide optimal exhaust expansion over the full range of ambient pressure, and represents a compromise
solution. Rockets launched from high altitude can be optimized for lower ambient pressure, thus achieving greater thrust over the entire operating
regime.

Propellant is conserved because the air-breathing carrier aircraft lifts the rocket to altitude much more efficiently with the use of engines that do
not require on-board storage of an oxidizer. This allows the launch system to conserve a significant amount of mass that would otherwise be reserved
for fuel, reducing the overall size. A larger fraction of the rocket mass can then include payload, reducing payload launch costs. It is also possible
to make use of higher-impulse fuels precluded from surface launches due to their toxicity, such as those containing beryllium or fluorine.

Air launch to orbit offers the potential for aircraft-like operations such as launch on demand, and is also less subject to launch-constraining
weather. This allows the aircraft to fly around weather conditions as well as fly to better launch points, and to launch a payload into any orbital
inclination at any time. Insurance costs are reduced as well, because launches occur well away from land, and there is no need for a launch pad or
blockhouse.[citation needed]

Air launch to orbit also works well as part of a combination launch system such as a reusable air-launched Single Stage to Tether launch vehicle
powered by a rocket or RBCC engine.

An additional benefit of Air launch to orbit is a reduced delta V needed to achieve orbit. This results in a greater payload to fuel ratio which
reduces the cost per unit mass to orbit. To further leverage the Delta V advantage, supersonic air launch to orbit has been proposed.[1]

However, the very TLDR version is the primary advantage is the ability to tailor your orbit inclination. The aircraft can take off from many, many
strips and then launch placing the sat at desired inclination immediately. Now, the sats have to spend more from both the rocket doing the best it
can and then spending a while phasing itself into the orbit really desired. That uses fuel. Using the fuel shortens the life time of the sat. You
can extend the sat life quite a while if you do an air launch.

However, to really reduce costs, assuming Burt and Mr Allen are doing this for commercial reasons, then they need to have a high launch rate.
Otherwise, this falls into the shuttle trap: large overhead to take care of the craft even if its reusable.

Interestingly, the DreamChaser is supposed to fly off this. Why? IDK, but supposedly…

This content community relies on user-generated content from our member contributors. The opinions of our members are not those of site ownership who maintains strict editorial agnosticism and simply provides a collaborative venue for free expression.